For a man as sharply dressed and well spoken as Pep Guardiola, the Bayern Munich coach is surprisingly good at courting controversy.

From his long-running touchline spats with Jose Mourinho during their fiery Classico encounters at Barcelona and Real Madrid, to his very public falling out with his successor at the Catalan club - the late Tito Vilanova - Pep doesn't appear to hold his own conduct to quite the same exacting standards as that of his players on the pitch.

The season hasn't even started yet and Guardiola is already making headlines once again, this time for failing to shake the hand of opposite number Caleb Porter during a supposed friendly game between his Bundesliga-winning side and an MLS All-Stars 2014 XI.

The Spanish manager appeared incensed over a poorly-timed challenge by Osvaldo Alonso, but being on the losing end of a 2-1 scoreline can't have helped his mood.

Pep made it clear to his opposite number precisely what he thought of the incident at the end of the game with a "one-fingered wave off", according to the MLS commentators.

He then appeared to do his best to ignore Porter when the MLS manager approached him on the pitch.